The absence of McPharlin and Dawson leaves only Michael Johnson as a first-choice tall in defence.

And with Port Adelaide boasting multiple threats in attack, the double injury blow comes at the worst possible time for Fremantle.

Power spearhead Jay Schulz leads the Coleman Medal race with 24 goals, while 199cm Justin Westhoff, All-Australian Chad Wingard and former Bomber Angus Monfries also have the potential to wreak major damage.

The Dockers have recalled Alex Silvagni for his first game of the year, while forward Chris Mayne is set to play in defence.

Mayne performed well on Eagles forward Jack Darling in the second half last week, while Silvagni has had his moments during his stop-start 39-game career.

Ruckman Zac Clarke is another option to throw back.

But they are no match for the defensive combination of McPharlin and Dawson.

McPharlin, 32, not only shuts down the opposition's best forward, but his rebound sets up numerous attacking thrusts.